Measuring systems allowing several dimensions of a part to be measured simultaneously are known. These devices, also known by the designation multipoint measuring systems, are typically used in operations of quality control and dimensional verification of finished parts, in particular machined parts, but not only of parts obtained through automatic machining.
These systems generally comprise a system for positioning the part to be measured and the positioning of the measuring elements. Furthermore, they often include stops for positioning the mobile parts in a repeatable way in order to measure a part placed in the system. There are generally carriages or mobile elements supporting comparators or probes for one-dimensional measurements that come into contact at the same time at several predetermined points of the part. The probes, by means of high-precision transducers, supply an electric measuring signal which is transmitted to an external electronic interface that controls the probe, then the results are generally sent to a computer system that allows the parameters to be analyzed and computed and dimensional statistics of values such as thickness, diameter, perpendicularity, conicity, parallelism, excentricity etc. to be performed.
The known multipoint measuring devices use both length probes with a sliding probe tip as well as lever probes with a pivoting probe tip, according to necessity and the configuration of the parts to be measured. Transducers are most often transducers of an inductive type, such as for example LVDT (Linear Variable Differential Transformer) or inductive half-bridges, and typically supply measurements with a precision on the order of 1 μm in a measurement range of several millimeters. Due to space requirements, the electronics are often external to the transducer.
Document WO2005109166 describes a measuring probe having a sliding probe tip for measuring the surface of a mechanical part. An inductive transducer comprised in the probe makes it possible to convert the displacement of the probe's mobile part into an electric signal that is then transmitted to a display device or an external computer. The communication towards the computer takes place through a USB or wireless interface.
One disadvantage of known probes is that each must be connected to an external measuring electronics that transforms the analog data coming from the inductive sensor and transforms and transmits them to a monitoring system. In the case of wireless probes, the measurements are triggered by a measurement trigger signal and the measurements are then stamped with the time of the measurement, as the systems have variable delays. Each measurement element can thus have a measurement delay which causes errors that are difficult to correct. It is difficult to guarantee the synchronization of the transfers of the different elements when it is not known what they are doing neither at the instant of the measurement nor at the moment when the results are sent. Furthermore, these systems rest on asynchronous transmission protocols between when the measurement is triggered and the measurement is recovered, which makes the transmission in these systems complicated, slow and renders the data not always comparable. Finally, these systems can be caused to receive useless information at the time of measurement, which can cause delays in the processing.